Gate valve

ABSTRACT

An embodiment includes a gate valve comprising: a valve body including a cavity coupled to a channel having proximal and distal portions; a gate to seal and unseal the channel; proximal and distal seats adjacent the gate; wherein (a) the proximal seat traverses towards the gate and stops at a first position when the gate is closing and the proximal channel portion is more highly pressurized than the cavity, and (b) the distal seat slides away from the gate and stops at a second position when the gate is closing and the cavity is more heavily pressurized than the distal channel portion. Other embodiments are described herein.

This application is a continuation of U.S. patent application Ser. No.14/706,065, filed on May 7, 2015 and entitled “Gate Valve.” The contentof the above application is hereby incorporated by reference.

TECHNICAL FIELD

Embodiments of the invention concern valves and, in particular, gatevalves.

BACKGROUND

Gate valves typically have a valve body with a flow passage extendingthrough it. The flow passage intersects a central cavity. A gate isprovided to move through the central cavity to block the flow passage.Seal rings are used to bridge a gap between the valve body and the gateto prevent fluid from flowing around the gate and into the valve body athigh pressure when the gate blocks the flow passage. When fluid flowsaround the gate and into the valve body at high pressure over aprolonged period of time the gate valve can develop leaks at significantcost and effort to the operator of the valve.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of embodiments of the present invention willbecome apparent from the appended claims, the following detaileddescription of one or more example embodiments, and the correspondingfigures. Where considered appropriate, reference labels have beenrepeated among the figures to indicate corresponding or analogouselements.

FIG. 1 illustrates a gate valve assembly in an embodiment of theinvention.

FIG. 2 illustrates two seat assemblies on either side of a gate (in aclosed position) in an embodiment of the invention.

FIG. 3 illustrates the location of seat pockets in an embodiment of theinvention.

FIG. 4 illustrates seat pockets in an embodiment of the invention.

FIG. 5 illustrates two seat assemblies adjacent the gate (in a closedposition) in an embodiment of the invention.

FIG. 6 illustrates an exploded view of a gate and seat assemblies in anembodiment of the invention.

FIG. 7 illustrates gate valve function when the gate is fully closedwith no pressure upstream or downstream of the gate in an embodiment ofthe invention.

FIG. 8 illustrates gate valve function when the gate is fully closedwith high pressure upstream of the gate in an embodiment of theinvention.

FIG. 9 illustrates gate valve function when the gate is partially closedwith pressure upstream and downstream of the gate in an embodiment ofthe invention.

FIG. 10 illustrates gate valve function when the gate is fully open withhigh pressure upstream and downstream of the gate in an embodiment ofthe invention.

FIG. 11 illustrates gate valve function when the gate is partiallyclosed with pressure upstream and downstream of the gate in anembodiment of the invention.

FIG. 12 illustrates gate valve function when the gate is fully closedwith high pressure upstream of the gate in an embodiment of theinvention.

FIG. 13 includes a process in an embodiment of the invention.

FIG. 14 includes an annular seal body in an embodiment of the invention.

DETAILED DESCRIPTION

Reference will now be made to the drawings wherein like structures maybe provided with like suffix reference designations. In order to showthe structures of various embodiments more clearly, the drawingsincluded herein are diagrammatic representations of structures. Thus,the actual appearance of the fabricated structures, for example in aphoto, may appear different while still incorporating the claimedstructures of the illustrated embodiments. Moreover, the drawings mayonly show the structures useful to understand the illustratedembodiments. Additional structures known in the art may not have beenincluded to maintain the clarity of the drawings. For example, not everygasket or port or coupling agent (e.g., screw) of a gate valve device isnecessarily shown. “An embodiment”, “various embodiments” and the likeindicate embodiment(s) so described may include particular features,structures, or characteristics, but not every embodiment necessarilyincludes the particular features, structures, or characteristics. Someembodiments may have some, all, or none of the features described forother embodiments. “First”, “second”, “third” and the like describe acommon object and indicate different instances of like objects are beingreferred to. Such adjectives do not imply objects so described must bein a given sequence, either temporally, spatially, in ranking, or in anyother manner. “Connected” may indicate elements are in direct physicalcontact with each other and “coupled” may indicate elements co-operateor interact with each other, but they may or may not be in directphysical contact.

An embodiment includes a gate valve assembly having a valve body with anopening and a seat insert configured to fit into the opening of thevalve body. Embodiments including a “single seat configuration” removeleak paths, reduce machining costs, and reduce the number of parts(effectively reducing failure paths) for the system. This saves costsand increases reliability. By “single seat” such an embodiment does notrequire a seat retainer/seat insert and seat sealing mechanism, insteadrelying only upon a single component seat sealing mechanism. Forexample, Patent Application PCT/US2014/045692 (entitled “Gate Valve withSeat Assembly” and filed Jul. 8, 2014) and U.S. Patent ApplicationPublication Number US2015/0014568 (entitled “Gate Valve with SeatAssembly” and filed Jun. 23, 2014) describes a seat insert that couplesa seat to a valve body. However, in some “single seat configuration”embodiments described herein no such seat insert is used. Instead, insome embodiments a monolithic seat directly interfaces the valve body.

FIG. 1 illustrates a gate valve assembly in an embodiment. The gatevalve assembly is provided with a hand wheel 629, a stem packing seal605, a bonnet 603, an operating stem 634, a gate 602, a valve body 635,studs 607, nuts 608, and a gate-seat assembly 600. In operation, thegate valve seating assembly 600 is configured so as the hand wheel 629is actuated (or some similar operator is actuated), the operating stem634 is moved so the gate 602 can either close or open the channel 601 inthe valve body 635. When the gate 602 is in an open position, fluid isallowed to flow through the channel 601 (see FIG. 2) in the valve body635. When the gate 602 is in a closed position, the flow of fluid isdisrupted within the channel 601. A gate valve seating assembly 600 isprovided between the valve body 635 and the gate 602 to prevent orlessen leakage of fluid from the channel 601 into cavity 609 when thegate is closed. If this leakage is not prevented, over time highpressure fluid in cavity 609 places pressure on stem packing seal 605,leading to eventual system failure and/or undesired maintenance.

In an embodiment, a two-way gate valve assembly is provided such thateither the upstream line or the downstream line can be attached toeither side 610′, 611′ of the valve body. Thus, what is a “distal” seatfor flow in one direction is a “proximal” seat when flow reverses. Asused herein “distal” and “downstream” are used interchangeably and“proximal” and “upstream” are used interchangeably.

The bonnet 603 is mounted to the valve body 635 by studs 607 and securedwith hex nuts 608. The bonnet 603 is sealed with respect to the valvebody 635 by a bonnet gasket 628. The seal of the stem packing 605provides a seal between the bonnet 603 and the operating stem 634. Theseat assemblies between the valve body 635 and the gate 602 aredescribed in greater detail with reference to FIGS. 5 and 6. Attached tothe bonnet 603 are autoclave fittings 612′ and 625′. Autoclave fitting612′ is a bleed port or a pressure release valve which allows anoperator to release pressure with respect to the valve body and thebonnet. Autoclave fitting 625′ is a grease port fitting that allows anoperator to introduce a lubricant to the gate 602 and seat assembly 600.

FIG. 2 provides a zoomed in view of gate valve seat assembly 600. Seatassemblies 650, 651 (embodiments of which are shown in FIGS. 5 and 6)are positioned to surround channel 601 and may be cylindrical inconstruction and may insert into cylindrical shaped pockets (e.g., seatpockets 621, 622 of FIGS. 3 and 4). The gate valve assembly 600comprises a gate 602 which is used to control fluid flow through theflow bore channel 601 when the gate 602 is actuated. The assembly 600also includes first and second seats 604, 606 (which comprise part ofthe seat assemblies shown in FIGS. 5 and 6) on opposing sides of thegate 602. The first and second seats are placed in the seat pockets(which are formed within valve body 635), which in an embodiment areinlayed with corrosion resistant material.

In some embodiments, annular seal assemblies 619, 620 (a close up ofwhich is provided in FIG. 14) are positioned between the seats 604 and606 and the seat pockets 621, 622. These seal assemblies 619, 620 may beO-rings and/or spring energized type seals. FIG. 14 provides a zoomed inview of a spring energized type seal used in the annular sealassemblies. It is comprised by a hat ring 666 which, when applied withpressure, stabilizes the spring 667. The spring is energized by theclearance between the seat pocket and seat surfaces, meaning wheninstalled, the spring is compressed and is actively pushing outwardagainst the compression. This forces the seal casing 668 against boththe pocket 621 and seat 604 surfaces. When pressure enters the concavespring 667 it causes the spring to flare further forcing the seal casing668 against the sides of both the seat and seat pocket. This seal onlyworks with pressure applied to the concave side, in order to seal frompressure coming the other direction from the valve body the same seal ismirrored on the other side of the spacer 669. Spacers 669, 669′ are oneither side of annular ring 699. Annular ring 699 resides within annulargroove 698, which is located on the outer surface of seat 604. In anembodiment groove 698 is on step 623 (see FIG. 2), whose outer surfacehas a smaller outer diameter than outer surface 623′. Any other type ofmechanically viable seal may also be used in varying embodiments. Theseals 611 may be composed of polymer, elastomeric, non-elastomeric,and/or metallic material or some combination thereof and are configuredto be suitable to any application depending on the variability ofenvironmental factors such as flow pressure (low/high) and temperature.

The seal assemblies 619, 620 are further adapted to be positioned onsteps 623, 624 on the seats 604 and 606. The seats 604 and 606 arefurther configured to receive and accommodate springs 613 and 614 (shownin greater detail in FIG. 2), which are positioned between the seats andseat pocket protectors 615 and 616. The seats are further configured toreceive and accommodate trash rings 617 and 618. In an embodiment, thetrash rings 617, 618 provide additional protection against any debristhat may enter the space (e.g., space 673) between the seat 604 (and/orseat 606) and the valve body 635. This allows for protection of thespace between the valve body and seat as well as providing protectionfor the seal assemblies 619, 620.

Springs 613 and 614 may include several components, spacers, bushings,rings, and the like as desired to provide an initial seal force. In anembodiment, springs 613 and 614 are circular and surround channel 601.In an embodiment the seat pocket protectors 615 and 616 are used toprevent the springs from creating an indention in the seat pocket innerface 627. In an embodiment, the seat pocket protectors 615, 616 are amaterial of lower hardness in respect to the material of the seat pocketinner face 621 and the material of the seat/valve body 635. For example,if there were no protector and seat pocket inner faces 621, 622 wereinlayed with a non-corrosive material (e.g., hardness=160 HBW) and thesprings 613, 614 were made of a normal material (e.g., AISI 4130 with ahardness=200 HBW), as they compress together due to force from springs613, 614 or fluid pressure, the harder springs 613, 614 would wear intothe softer seat pocket inner face inlayed material causing surfaceindentions in the inlayed material, which leads to leaks. To preservethe seat pocket inner face and any inlayed non-corrosive material andprevent leaking, a sacrificial part, in this case a seat pocketprotector 615, 616, is put between the pocket inner faces 621, 622 andsprings 613, 614. In an embodiment the pocket protector has a hardnessthat is less than both the pocket inner face 621, 622 and the springs613, 614. For the sake of this example, the protector 615, 616 is madeof common 316 stainless steel, hardness of 80 HBW, which means that thismaterial will be slowly ground down between the pocket inner face 621,622 and the springs 613, 614. This allows for protection of thecorrosion resistant material inlayed and/or welded into the seat pocket621, 622 of the valve body 635. Further, the seat pocket protectors 615,616 keep the corrosion resistant material inlayed and/or welded into theseat pocket 621, 622 from galling, which is when a material is pulledfrom a contact surface which is under compression.

The arrangement of the protectors, springs, seal assemblies, and seatsenable a “dynamic seal” between the valve body seat pocket and theseats. As used herein, with a “dynamic seal” the sealing interfacebetween two or more surfaces (e.g., seat 604 and gate 602) has onesurface in motion (e.g., gate 602) relative to the other surface (e.g.,seat 604). For example, if the seat 604 is moving while the seal(between seat 604 and gate 602) is not moving, the interface is dynamicand the seal must contain the liquid (e.g., from bore 601) along thefull traveling path of the interface. As another example, if the seat604 is moving while the valve body 635 is not moving, the interface isdynamic and the seal must contain the liquid (e.g., from bore 601) alongthe full traveling path of the interface. This configuration ofprotectors, springs, seal assemblies, and seats allows for continuouscontact between seats 604, 606 and the surfaces of the gate 602 throughthe spring force provided by the springs 613 and 614. The springs 613,614 provide a sealing force to the seats 604, 606, allowing the seat andgate interface to seal, while the spring energized seal assembliesretain their seals between the seat 604, 606 walls and the seat pocket621, 622 walls.

The above arrangement of the components of the valve assembly 600provides that the pressure from the flow bore channel 601 effectivelyseals all of the passages by the seal assemblies 619, 620. They alsoallow for continuous contact between the seats 604 and 606 and the gate602 by use of springs 613 and 614 and/or fluid pressure, therebyallowing for sealing at maximum designed working pressures (as well aslow pressures). The ability for a valve to fully seal at both low andhigh pressure is critical for many dynamic and rigorous up-streamapplications (e.g., choke and kill manifolds and well-head equipment). Avalve for these applications should fully seal throughout its full ratedpressure range: 1 psi to maximum rated pressure, which may include 5,000psi, 10,000 psi, 15,000 psi, 20,000 psi, and greater. The ability for avalve to fully seal at both low and high pressures allows a valve to begiven a higher classification. In contrast, conventional gate valveshave difficulty gaining a “high classification” because their sealingconfiguration/mechanisms require 1,500-3,000 psi pressure to fullyengage and completely seal (i.e., does not seal at low pressure). In theevent that one of these conventional valves needs to seal at a lowpressure (e.g., 500 psi or less), it must first be over-pressured tocreate its seal, then the pressure must be decreased—all of which iscumbersome or not possible for the operator. Such a conventional processcreates room for application error, for instance, if a choke used on a10,000 psi line malfunctions into a low-pressure setting of 300 psi whenthe line is opened, the common valve further down the line will not havethe energizing pressure required to seal, which would result in anuncontrolled flow around the gate. Energizing pressure defines thepressure required to compress a seal enough against a sealing surface toresist the force, due to fluid pressure, trying to push the seal awayfrom the sealing surface. To do this, the compressive force must be morethan the fluid force. However, embodiments described herein eliminate orlessen the possibility of this scenario in part, at least partially, tosprings 613, 614.

Preexisting valves include a seat retainer (or “seat insert” as referredto in U.S. Patent Application Publication Number US2015/0014568), seat,and gate. This allows for three different leak paths: (1) a seal betweenthe seat retainer and seat pocket, (2) a seal between the seat retainerand seat, and (3) a seal between the seat and the gate. For such adesign configuration operation is as follows: as the upstream begins topressurize, fluid fills the clearance between the seat pocket/seatretainer interface as well as the seat retainer/seat interface. Thisleaves the retainer seals in a low energy state (i.e., they do not havethe required force to create a seal) causing the fluid to flow throughthe seat pocket/seat retainer interface into the valve cavity. As thefluid fills the cavity, it enters the clearance of the downstream seatpocket/seat retainer and seat retainer/seat interfaces, initiallyleaking into the downstream channel. When pressure builds, the seals ofdownstream interfaces (seat pocket/seat retainer interface as well asthe seat retainer/seat interface) will see pressure from both thechannel and the body valve cavity, resulting in fully energized sealsbetween the gate/seat interface, seat/seat retainer interface, and seatretainer/seat pocket interface as the seat and seat retainer are drivenapart, fully sealing the downstream. Once the downstream seals, theupstream seals also see full pressure from both the channel side andcavity side, creating full seals as the upstream seat and seat retainerare also fully driven apart, finally creating a fully sealed channelthroughout the valve (both upstream and downstream).

This design configuration has six total potential leak paths (the threeinterfaces on each of the upstream and downstream sides of the gate),which are increased over time because the seals wear due to friction asthe parts rub against one another. If a single seal fails on thedownstream side it is possible the whole valve function will fail,requiring immediate maintenance. Additionally the incorporation of somany parts causes unnecessary wear on components, requiring morefrequent maintenance.

In contrast, an embodiment provides a more streamlined and more reliablealternative that requires less maintenance and provides more efficientsealing. FIG. 13 includes a process in a “single seat” embodiment of theinvention. The process concerns the embodiment of FIGS. 5-12, 14. Theembodiment only features two leak paths on either side of the gate, fora total of four leak paths. For example, the two different leak pathsare: (1) the dynamic seal between the seal assembly 620 and seat pocket621, and (2) the dynamic sealing interface between the seat 604 and thegate 602.

This embodiment allows for full sealing at both the de-energized (see,e.g., FIG. 7, where seal 652 is not energized due to lack of pressure inchannel 601) and full-energized (see, e.g., FIG. 10, where seal 652 isenergized due to pressure in channel 601) scenarios on both the upstreamand downstream sides. If the upstream seal were to fail, the designwould function as a common downstream sealing valve, providing two valvefunctions in one. In other words, conventional valves not only have morefailure modes but also have no fail-safe mechanism, as opposed toembodiments described herein. Specifically, if the downstream seal failsin embodiments described herein, the upstream seal will still seal withthe gate. Conversely, if the upstream seal fails, the downstream sealwill still seal with the gate. Lastly, the seat assembly embodiment ofFIGS. 5-12 features primarily only two moving parts (the proximal anddistal seats) thereby lowering maintenance and machining costs.

The surfaces of the seats 604 and 606 are adapted to be able to sealwith gate 602. The surfaces may be provided with various indentations ora finished surface having a surface area that may be larger or smallerthan other surface areas of the seat to affect a variable force actingagainst the gate so the sealing force that pushes the surfaces togetheris greater than the force that would urge the two surfaces apart.

FIGS. 5 and 6 illustrate a first seat assembly 650 (604, 620, 613, 615,617) and a second seat assembly 651 (606, 619, 614, 616, 618) and FIG. 7includes those assemblies positioned within a valve body 635 when thegate 602 is in a closed position. The first and second seat assemblies650, 651 are positioned on both the upstream and downstream portions ofthe valve body 635. As a result, the seat assemblies 650, 651 provideimproved sealing on both the upstream and downstream of the valve body.High pressure/High temperature seal assemblies 619, 620 are positionedbetween the seats and the valve body seat pocket walls. Although highpressure/high temperature seals are used in this embodiment, any type ofseal may be used. With the low pressure conditions of FIG. 7, self seals682 are present due to the spring force of spring 667. This is an“annular seal”. There are also seals 652, 653, 654, 655 due to springforce (see “spring force” label in FIG. 7) from springs 613, 614.

In FIG. 8 the gate 602 is closed and fluid enters into the channelcreating pressure (e.g., 20,000 psi). This causes the fluid to attemptto navigate around the seat (i.e., at the seat face/gate interface 662,664 and seat face/valve body interface 678). Another seat face/valvebody interface is indicated at element 679. The seal assembly 620 isspring energized by spring 667 (see FIG. 14), which effectively sealsthe leak paths/seals 656, 657 to the valve body cavity 609. While thepressure attempts to escape through the gaps 656, 657 between the seatassembly 650 and seat pocket 621 it also pushes the seat face againstthe gate surface 602 at seat face/gate interface 662, 664 and seals theleak paths/seals 652, 654 to the body cavity 609. This configurationcreates a fully sealed valve channel no matter the direction of theflow. With the high pressure condition of FIG. 8, self seal 682 ispresent due to spring 667. However, seals 652, 653, 654, 655 are nowsealed due to bore fluid pressure (labeled “bore fluid pressure” in FIG.8). Sealing assembly 619 self-seals leak paths/seals 658, 659.

In FIG. 9 during operation of the gate, transitioning from closed toopen, fluid 681 enters into the channel 601 and the valve body cavity609. Valve body fluid is trapped in cavity 609 at full wellbore pressurewhen the valve is fully opened (FIG. 10). This is achieved by the wellbore pressure energizing the seat on the upstream and downstream side.Specifically, as shown in FIG. 10, the well bore pressure moves theseats 604, 606 toward the seat face/gate interfaces 662, 663, 664, 665of the gate, creating seals 652, 653, 654, 655 between the gate 602 andthe seat assemblies 651. As a result, the valve body pressure is trappedin the body cavity. In FIG. 10, seals 682 are self annular seals andseals 652, 653, 654, 655 are seals due to bore fluid pressure.

In FIG. 11, during the operation of the gate, transitioning from theopen to close, the downstream pressure begins to decrease (e.g., from20,000 psi to 5,000 psi), creating a pressure differential between thedownstream area (5,000 psi) and body cavity 609 (20,000 psi in area609). Concurrently, the decreasing downstream pressure also de-energizesthe seat 606, removing the sealing force creating seal 653, 655 betweenthe gate and seat. The large pressure trapped in the body cavity 609separates the gate from the downstream seat, and escapes (see fluid 684)downstream via paths/weakened seals 653, 655. In FIG. 12, once fullyclosed the still energized upstream seat 604 seals 652, 654 against thegate 602, effectively closing the valve. There are self seals 682 aswell as well bore pressure induced seals 652, 653, 654, 655.

The process 1300 of FIG. 13 will now be addressed in relation to FIGS. 7to 12. In element 1305, the gate is closed with no channel pressure.FIG. 7 depicts gate 602 closed and no pressure in channel 601. As aresult, both the proximal/upstream seat 604 and the distal/downstreamseat 606 are pushed toward the gate by springs 613, 614. However, seals652, 653, 654, 655 are sealed but not at a level that can preventleaking should typical full “well bore” pressure of 20,000 psi beexperienced. However, seals 652, 653, 654, 655 are effective lowpressure seals.

In element 1310 gate 602 is closed with upstream pressure increasing.Fluid from upstream fills the proximal channel 601. The fluid enters thegap 673 between the seat pocket 621 and the seat 604, creating pressureon the seal assembly 620 thereby sealing the outer annular surface ofthe seat and the inner annular surface of the seat pocket (see interface678). Concurrently, this pressure pushes the seat further towards thegate, energizing the seat and creating a seat-gate seal 652, 654. Pleasenote that distance 671 (FIG. 7) is smaller than distance 672 (FIG. 8)for void 673 due to upstream pressure pushing on the gate 602 andcompressing spring 614 on the downstream side.

In element 1315 gate 602 is closed with upstream pressure at its maximum(FIG. 8). By “maximum” this just means maximum in this particular fluidflow episode and is not meant to mean the maximum pressure the devicecan handle before failure. When upstream is at full working pressure(e.g., 20,000 psi), the proximal/upstream seat 604 is fully sealed(seals 652, 654, 682) and the distal/downstream seat 606 is also in asealing position due to the force of the upstream seat 604 pushing onthe gate 602 (i.e., springs 613, 614 only serve to provide enoughsealing force for low pressures). Seals 682 from annular seals 619, 620are always in existence and are not necessarily dependent (or asdependent) on pressure differentials between chamber 601 and cavity 609as other seals 652, 653, 654, 655. They are “self seals”.

In element 1320 gate 602 is barely open with max upstream pressure inchannel 601 (FIG. 9). As the gate starts to open the body cavity 609 isat ambient pressure. As the gate clears the seat, upstream fluid flowsinto the body cavity (681) and into the gap 674 between the downstreamseat pocket 622 and seat 606.

In element 1325 gate 602 is partially open with max upstream pressure.Once the body cavity 609 is full, pressure is applied to the body cavity609 and the distal seat assembly 651. This (along with force in void674) energizes the seat 606, pushing the downstream seat 606 towards thegate 602. Concurrently, the fluid in the valve cavity 609 is pressurizedup to full pressure.

In element 1330 gate 602 is fully open with max channel pressure inchannel 601 (FIG. 10). Fluid in downstream channel 602 puts pressure ondownstream seat 606. This pushes distal seat towards gate 602, creatinga downstream seal and fully sealed valve channel. Please note thatdistance 683 (FIG. 9) is smaller than distance 685 (FIG. 10) for void674. The body cavity 609 fluid is sealed at max pressure (wellborepressure).

In element 1335 gate 602 is barely closed with max channel pressure inchannel 601 along both the proximal and distal portions of channel 601(FIG. 11). As the gate closes the body cavity 609 is at max pressure. Asthe gate clears the seat, downstream fluid pressure decreases (e.g.,5,000 psi), creating a pressure differential between the high pressurecavity 609 (e.g., 20,000 psi) and low pressure downstream channel.

In element 1340 gate 602 is partially closed with max channel pressurein the upstream portion of channel 601. With gate 602 half-closed distalchannel pressure is much less than cavity and upstream channel pressure.Lowered pressure de-energizes the distal seat 606 so cavity 609 fluid(at 20,000 psi) separates the seat face from the gate (see seals 653,655) at seat/gate interface 663, 665, allowing cavity fluid to emptydownstream (684) and dropping cavity 609 pressure to 5,000 psi or less.

In element 1345 gate 602 is closed with upstream pressure at a maximum.When fully closed, flow is contained in the upstream portion of channel601. The upstream seat 604 previously experienced full pressure (FIG. 8)so upstream seat 604 is still energized and holds its seal 652, 654 withgate 602.

Example 1 includes a gate valve assembly comprising: a valve body havinga channel extending from a distal end to a proximal end; a gateconfigured to be moved from a first position to a second position, thesecond position being when the gate is positioned in the channel of thevalve body between the distal end and the proximal end of the valvebody; at least one seat configured to be positioned within a pocket ofthe valve body; a seal assembly adapted on a step of the seat positionedbetween the valve body wall and the seat, wherein the seal is a dynamicseal providing no gaps and/or spaces between the seat and the valve bodyallowing no fluid to flow into the valve body.

In example 2 the subject matter of the Example 1 can optionally includewherein the gate valve assembly further comprises a trash ring, whichcomprises a perforated metallic ring that acts as a filter and ispositioned within a groove of the seat.

In example 3 the subject matter of the Examples 1-2 can optionallyinclude wherein the gate valve assembly further comprises a gap betweenthe seat and valve body.

In example 4 the subject matter of the Examples 1-3 can optionallyinclude wherein the trash ring includes a plurality of holes.

In example 5 the subject matter of the Examples 1-4 can optionallyinclude wherein when the gate is in a closed position, the seat and thegate have metal to metal contact.

In example 6 the subject matter of the Examples 1-5 can optionallyinclude wherein a disc spring is positioned between the seat and thevalve body.

Example 7 includes a gate valve assembly comprising: a valve body havinga channel extending from a distal end to a proximal end; a gateconfigured to be moved from a first position to a second position, thesecond position being when the gate is positioned in the channel of thevalve body between the distal end and the proximal end of the valvebody; at least one seat configured to be positioned within a pocket ofthe valve body; a seal assembly adapted on a step of the seat positionedbetween the valve body and the seat, wherein the seal assembly is adynamic seal providing no gaps and/or spaces between the seal and thevalve body allowing no fluid to leak into the valve body.

In example 8 the subject matter of the Example 7 can optionally includewherein the gate valve assembly further comprises a trash ringpositioned within a groove of the seat and valve body.

In example 9 the subject matter of the Examples 7-8 can optionallyinclude wherein the gate valve assembly further comprises a gap betweenthe seat and the valve body.

In example 10 the subject matter of the Examples 7-9 can optionallyinclude wherein the trash ring includes a plurality of holes

In example 11 the subject matter of the Examples 7-10 can optionallyinclude wherein a disc spring is positioned between the seat and valvebody.

The above examples and embodiments provide many advantages overconvention systems such as, for example, (1) only two potential leakpaths (between seat and seat pocket and between the seat and gate) asopposed to three potential leak paths (between seat retainer and seatpocket, between the seat retainer/insert and the seat, and between theseat and gate), (2) does not require a secured insert such as a seatretainer, and (3) reduces machining and replacement parts (e.g., becauseno seat retainer is needed).

Example 1a includes a gate valve comprising: a valve body including acavity in fluid communication with a channel, having proximal and distalchannel portions, which extends between proximal and distal valve bodyportions; a gate configured to seal the channel in a closed gateposition and unseal the channel in an open gate position; a proximalseat between the proximal valve body portion and the gate and a distalseat between the distal valve body portion and the gate; wherein (a) theproximal seat slides towards the gate and then stops at a first positionwhen the gate is in the closed gate position and the proximal channelportion includes fluid more highly pressurized than fluid included inthe cavity, and (b) the distal seat slides away from the gate and thenstops at a second position when the gate is in the closed gate positionand the cavity includes fluid more heavily pressurized than fluid in thedistal channel portion.

For example, in an embodiment as soon as there is a pressuredifferential (e.g., the upstream side has more pressure acting on thesurface area of the seat than the downstream side), the seat and gatewill move. The seat and gate will have fully moved laterally before thegate has completely transitioned from an open position to a closedposition. Afterwards, there will be no more movement before the gate isfully closed, which is why there are bevels on the seats in someembodiments—to allow the gate to slide into position.

For example, FIGS. 5-12 depict an embodiment of a gate valve comprising:a valve body 635 including a cavity 609 in fluid communication with achannel 601. The proximal seat 604 slides towards the gate 602 and thenstops at a first position when the gate is in the closed gate positionand the proximal channel portion includes fluid more highly pressurizedthan fluid included in the cavity (FIG. 8). Further, the distal seat 606slides away from the gate and then stops at a second position when thegate is in the closed gate position and the cavity includes fluid moreheavily pressurized than fluid in the distal channel portion (FIGS. 11and 12).

The slide of the distal seat away from the gate may occur before thegate is fully closed. The slide of the proximal seat towards the gatemay occur before the gate is fully closed.

An alternative embodiment of Example 1A includes a gate valvecomprising: a valve body including a cavity in fluid communication witha channel, having proximal and distal channel portions, which extendsbetween proximal and distal valve body portions; a gate configured toseal the channel in a closed gate position and unseal the channel in anopen gate position; a proximal seat between the proximal valve bodyportion and the gate and a distal seat between the distal valve bodyportion and the gate; wherein (a) the proximal seat slides towards thegate and into a first position when the gate is in the closed gateposition and the proximal channel portion includes first fluidpressurized at more than 100 psi, and (b) the distal seat slides awayfrom the gate and into a second position when the gate is in the closedgate position and the cavity includes second fluid more heavilypressurized than third fluid in the distal channel portion.

In example 2a the subject matter of Example 1a can optionally includewherein the proximal seat directly contacts the gate in the firstposition.

For example, a metal to metal seal occurs at seal 652.

An alternative embodiment of example 2a includes the subject matter ofExample 1a and can optionally include the proximal seat slides along aninterface with the valve body and towards the gate and then stops at afirst position when the gate is in the closed gate position and theproximal channel portion includes fluid more highly pressurized thanfluid included in the cavity.

For example, a vertical axis may be orthogonal to a horizontal axis thatextends along channel 601. The vertical axis may intersect both theproximal seat and the valve body. The interface may be a direct orindirect connection between the proximal seat and the valve body.

In example 3a the subject matter of the Examples 1a-2a can optionallyinclude wherein the proximal seat directly contacts the gate in thefirst position.

For example, a metal to metal seal occurs at location/interface 662.

In example 4a the subject matter of the Examples 1a-3a can optionallyinclude wherein the proximal seat is monolithic.

For example, seat 604 is uniform and formed from a single piece ofmaterial. However, in other embodiments the seat may be non-monolithicand be an assembly of non-uniform parts. In an embodiment the monolithicseat simultaneously contacts the gate and valve body during the pressureconditions addressed in FIGS. 7-12.

In example 5a the subject matter of the Examples 1a-4a can optionallyinclude wherein in the first position the proximal seat simultaneouslyprovides a first seal directly with the gate and a second seal directlywith the valve body.

For example, seals 652, 682 exist simultaneously.

In example 6a the subject matter of the Examples 1a-5a can optionallyinclude wherein the proximal seat slides away from the gate and into athird position when the gate is in the closed gate position and theproximal channel portion includes fluid less pressurized than fluidincluded in the cavity.

While this is not depicted in FIGS. 5-12, this situation may occur incertain conditions.

In example 7a the subject matter of the Examples 1a-6a can optionallyinclude wherein the proximal seat includes a first seat face separatedfrom a first valve body face by a first void having a first length inthe first position and a third length in the third position, the firstlength being greater than the third length.

An example of such a void includes void 673. Further, an example of“first length” is length 672 (FIG. 8) and an example of “third length”is length 671 (FIG. 7).

In example 8a the subject matter of the Examples 1a-7a can optionallyinclude wherein in the first position the void includes fluid that is influid communication with fluid in the proximal channel portion.

As mentioned above, fluid may flow from chamber 601 into void 673 tocause seat 604 to slide towards gate 602.

In example 9a the subject matter of the Examples 1a-8a can optionallyinclude wherein the distal seat slides towards the gate and into afourth position when the gate is in the closed gate position and thedistal channel portion includes fluid more highly pressurized than fluidincluded in the cavity.

An example of this occurs in FIGS. 9 and 10.

In example 10a the subject matter of the Examples 1a-9a can optionallyinclude wherein the distal seat includes a second seat face separatedfrom a second valve body face by a second void having a second length inthe second position and a fourth length in the fourth position, thefourth length being greater than the second length.

An example of such a void includes void 674. Further, an example of“second length” is length 683 (FIG. 9) and an example of “fourth length”is length 685 (FIG. 10).

In example 11a the subject matter of the Examples 1a-10a can optionallyinclude at least two ring seals, an annular spring seal located betweenthe valve body and the proximal seat, another annular spring seallocated between the valve body and the distal seat, and at least twoseat pocket protectors.

Example 12a includes a gate valve comprising: a valve body including acavity coupled to a channel having proximal and distal portions; a gateto seal and unseal the channel; proximal and distal seats adjacent thegate; wherein (a) the proximal seat traverses towards the gate and stopsat a first position when the gate is closed and the proximal channelportion is more highly pressurized than the cavity, and (b) the distalseat traverses away from the gate and stops at a second position whenthe gate is closed and the cavity is more heavily pressurized than thedistal channel portion.

However, another embodiment of example 12a includes a gate valvecomprising: a valve body including a cavity coupled to a channel havingproximal and distal portions; a gate to seal and unseal the channel;proximal and distal seats adjacent the gate; wherein (a) the proximalseat traverses towards the gate and stops at a first position when thegate is closed and the proximal channel portion is more highlypressurized than the cavity, and (b) the distal seat is static and sealsto the gate. Thus, there is an option with one static seal and onedynamic seal.

In example 13a the subject matter of the Examples 12a can optionallyinclude wherein the proximal seat directly contacts the gate and thevalve body in the first position.

In example 14a the subject matter of the Examples 12a-13a can optionallyinclude wherein the gate includes an aperture that aligns with thechannel when the gate is open.

An alternative version of example 14a includes the subject matter of theExamples 12a-13a can optionally include wherein the proximal seattraverses along an interface with the valve body towards the gate andstops at the first position when the gate is closed and the proximalchannel portion is more highly pressurized than the cavity.

In example 15a the subject matter of the Examples 12a-14a can optionallyinclude wherein the proximal seat is monolithic.

In example 16a the subject matter of the Examples 12a-15a can optionallyinclude wherein in the first position the proximal seat seals the gateand the valve body.

In example 17a the subject matter of the Examples 12a-16a can optionallyinclude wherein the proximal seat traverses away from the gate and intoa third position when the gate is closed and the proximal channelportion is less pressurized than the cavity.

In example 18a the subject matter of the Examples 12a-17a can optionallyinclude wherein the proximal seat is separated from the valve body by afirst void having a first length in the first position and a thirdlength in the third position, the first length being greater than thethird length.

In example 19a the subject matter of the Examples 12a-18a can optionallyinclude wherein in the first position the void includes fluid that is influid communication with fluid in the proximal channel portion.

In example 20a the subject matter of the Examples 12a-19a can optionallyinclude wherein the distal seat traverses towards the gate and into afourth position when the gate is closed and the distal channel portionis more highly pressurized than the cavity.

In example 21a the subject matter of the Examples 12a-20a can optionallyinclude wherein the distal seat is separated from the valve body face bya second void having a second length in the second position and a fourthlength in the fourth position, the fourth length being greater than thesecond length.

The foregoing description of the embodiments of the invention has beenpresented for the purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formsdisclosed. This description and the claims following include terms, suchas left, right, top, bottom, over, under, upper, lower, first, second,etc. that are used for descriptive purposes only and are not to beconstrued as limiting. These terms are relative to how one positions thegate valve embodiment. The term “on” as used herein (including in theclaims) does not indicate that a first element “on” a second element isdirectly on and in immediate contact with the second element unless suchis specifically stated; there may be a third element (e.g., gasket) orother structure between the first element and the second element. Theembodiments of a device or article described herein can be manufactured,used, or shipped in a number of positions and orientations. Personsskilled in the relevant art can appreciate that many modifications andvariations are possible in light of the above teaching. Persons skilledin the art will recognize various equivalent combinations andsubstitutions for various components shown in the Figures. It istherefore intended that the scope of the invention be limited not bythis detailed description, but rather by the claims appended hereto.

What is claimed is:
 1. A gate valve comprising: a valve body including a cavity configured to be in fluid communication with a channel, the channel: (a) having proximal and distal channel portions, and (b) extending between proximal and distal valve body portions; a gate configured to seal the channel in a closed gate position and unseal the channel in an open gate position; a proximal seat between the proximal valve body portion and the gate and a distal seat between the distal valve body portion and the gate, the proximal seat including an annular groove on an outer surface of the proximal seat; and a seal, which directly contacts the valve body and the proximal seat, including (a) a first ring contacting a first spring and a second ring contacting a second spring, (b) an annular ring included in the annular groove and between the first and second springs; wherein (a) the proximal seat is configured to slide towards the gate and stop at a first position when the gate is in the closed gate position, (b) the first and second springs are not included in the annular groove; (c) the first and second rings are not included in the annular groove; (d) the proximal seat directly contacts the gate in the first position, and (e) the proximal seat is monolithic.
 2. The valve of claim 1 wherein: (a) the proximal seat is configured to slide towards the gate and then stop at the first position when the gate is in the closed gate position and the proximal channel portion includes fluid more highly pressurized than fluid included in the cavity, (b) the distal seat is configured to slide away from the gate and then stop at a second position when the gate is in the closed gate position and the cavity includes fluid more heavily pressurized than fluid in the distal channel portion.
 3. The valve of claim 2, wherein the proximal seat is configured to slide away from the gate and into a third position when the gate is in the closed gate position and the proximal channel portion includes fluid less pressurized than fluid included in the cavity.
 4. The valve of claim 3, wherein the proximal seat includes a first seat face separated from a first valve body face by a first void having a first length in the first position and a third length in the third position, the first length being greater than the third length.
 5. The valve of claim 4, wherein: in the first position the first void is configured to include fluid that is in fluid communication with fluid in the proximal channel portion; the distal seat is configured to slide towards the gate and into a fourth position when the gate is in the closed gate position and the distal channel portion includes fluid more highly pressurized than fluid included in the cavity; the distal seat includes a second seat face separated from a second valve body face by a second void having a second length in the second position and a fourth length in the fourth position, the fourth length being greater than the second length.
 6. The valve of claim 1, wherein the proximal seat is configured to slide along an interface with the valve body and towards the gate and then stop at the first position when the gate is in the closed gate position and the proximal channel portion includes fluid more highly pressurized than fluid included in the cavity.
 7. The valve of claim 1, wherein: in the first position the proximal seat simultaneously provides a first seal directly with the gate and a second seal directly with the valve body; the second seal is provided via the seal.
 8. The valve of claim 7 comprising: an annular spring located between the valve body and the proximal seat; another annular spring located between the valve body and the distal seat.
 9. The valve of claim 8 comprising a seat pocket protector, wherein: the seat pocket protector includes a hardness that is less than a hardness of a face of the proximal seat; the hardness of the seat pocket protector is less than a hardness of a face of the valve body; the face of the valve body is configured to contact the seat pocket protector.
 10. A gate valve comprising: a valve body including a cavity coupled to a channel, the channel having proximal and distal portions; a gate to seal and unseal the channel; proximal and distal seats adjacent the gate, the proximal seat including an annular groove in a first annular outer surface of the proximal seat; a seal that directly contacts the valve body and the proximal seat, the seal including: (a) a first ring contacting a first spring and a second ring contacting a second spring, and (b) an annular ring included in the annular groove and between the first and second rings; and wherein (a) the proximal seat is configured to traverse towards the gate and stop at a first position when the gate is closed and the proximal channel portion is more highly pressurized than the cavity, (b) the first and second springs are not included in the annular groove, (c) the proximal seat is configured to directly contact the gate in the first position, (d) the first and second springs are each biased to press outwards towards both the valve body and the proximal seat.
 11. The valve of claim 10, wherein the proximal seat is configured to traverse along an interface with the valve body towards the gate and stop at the first position when the gate is closed and the proximal channel portion is more highly pressurized than the cavity.
 12. The valve of claim 10, wherein the proximal seat is monolithic.
 13. The valve of claim 12 wherein: the seal includes first and second casings; the annular ring is between the first and second casings.
 14. The valve of claim 13 wherein: the first annular outer surface includes a first outer diameter; the proximal seat includes a second annular outer surface having a second outer diameter that is greater than the first outer diameter; the first casing directly contacts the first annular outer surface but is not included in the annular groove.
 15. The valve of claim 14, wherein in the first position the proximal seat is configured to provide seals against both the gate and the valve body.
 16. The valve of claim 15, wherein: the first spring includes a first concave portion whose center of curvature is located proximal to the first spring; and the second spring includes a second concave portion whose center of curvature is located distal to the second spring.
 17. The valve of claim 16, wherein: the proximal seat includes a first seat face separated from a first valve body face by a first void; the first void is configured to be in fluid communication with the proximal channel portion; and the first ring is configured to be in fluid communication with the first void.
 18. The valve of claim 17 including a perforated ring between the first void and the proximal channel portion.
 19. The valve of claim 10, wherein: the proximal seat is configured to traverse away from the gate and into a third position when the gate is closed and the proximal channel portion is less pressurized than the cavity; the proximal seat is separated from the valve body by a first void having a first length in the first position and a third length in the third position, the first length being greater than the third length; in the first position the first void is configured to include fluid that is in fluid communication with fluid in the proximal channel portion; the distal seat is configured to traverse towards the gate and into a fourth position when the gate is closed and the distal channel portion is more highly pressurized than the cavity; the distal seat is configured to slide away from the gate and into a second position when the gate is closed and the cavity is more pressurized than the distal channel portion; the distal seat is separated from the valve body face by a second void having a second length in the second position and a fourth length in the fourth position, the fourth length being greater than the second length.
 20. A gate valve comprising: a valve body including a cavity coupled to a channel, the channel having proximal and distal portions; a gate to seal and unseal the channel; proximal and distal seats adjacent the gate; and a seal directly contacting the valve body and the proximal seat; a resilient member between the proximal seat and the valve body, the resilient member configured to bias the proximal seat towards the gate; wherein: the proximal seat is configured to traverse towards the gate and stop at a first position when the gate is closed and the proximal channel portion is more highly pressurized than the cavity; the seal includes: (a) a first ring coupled to a first spring and a second ring coupled to a second spring; (b) a first casing coupled to the first spring and a second casing coupled to the second spring, and (c) an annular ring; the first and second springs are each biased to press outwards towards both the valve body and the proximal seat; the proximal seat includes an annular groove on an outer surface of the proximal seat; the annular ring is included in the annular groove; the annular ring is between the first and second springs; the first and second springs are not included in the annular groove; the first and second rings are not included in the annular groove; the proximal seat is configured to directly contact the gate in the first position. 